Simple and Complex Working Memory Tasks Allow Similar Benefits of Information Compression

fabien mathy, Université Côte d'Azur

mustapha chekaf, Université Côte d'Azur

Nelson Cowan, University of Missouri, Columbia

Abstract

Because complex span tasks were designed to create a demanding
concurrent task, the average span is usually lower (4 ± 1 items) than in
simple span tasks (7 ± 2 items). One possible reason for the higher span of
simple span tasks is that participants can take profit of the spare time to chunk
a few stimuli into 4 ± 1 groups. It follows that the respective spans of
these two types of tasks could be equal (at around 4 ± 1) when regularities
are absent. We therefore predicted an interaction between task and chunkability,
supporting a single higher span for a simple span task using chunkable items.
However, observation of the spans in the non-chunkable vs. chunkable series
refuted the idea that chunking is important solely in simple spans. Indeed,
information compression processes contributed to performance levels to a similar
extent in simple and complex span tasks.